Observations of BZQ J0253+0006, a possible counterpart to IceCube-211116A, with the Zwicky Transient Facility

ATel #15051; Robert Stein (Caltech), Mansi Kasliwal (Caltech), Simeon Reusch (DESY) on behalf of the Zwicky Transient Facility
on 19 Nov 2021; 17:55 UT
Credential Certification: Robert Stein (rdstein@caltech.edu)

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We report observations of BZQ J0253+0006, reported as a possible counterpart (ATel #15046, #15049) to high-energy neutrino IceCube-211116A (GCN #31085). The Zwicky Transient Facility (ZTF) was undergoing telescope maintenance, and was thus unable to undertake ToO observations of this neutrino as part of our neutrino follow-up program. However, the region has been observed repeatedly as part of routine survey operations, most recently on 2021-11-14.35 UT. These images were processed through the ZTF image reduction pipelines at IPAC (Masci et al. 2019).

The blazar BZQ J0253+0006 has been previously detected by ZTF, with historical periods of flaring activity observed. A full ZTF lightcurve of the source is available at at this link. No flaring activity from source has been seen in recent months, with the most recent detection of r=21.20+/-0.23 on 2021-08-18.47 UT. The source has a quiescent flux comparable to the typical ZTF median limiting magnitude of ~21 in g/r, and thus routine detections are only expected during periods of enhanced electromagnetic activity.

In summary, we find no evidence of recent optical flaring on timescales >2 days, but cannot exclude more rapid variability coincident with the neutrino detection.

ZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC, USA; WIS, Israel; OKC, Sweden; JSI/UMd, USA; DESY, Germany; TANGO, Taiwan; UW Milwaukee, USA; LANL, USA; TCD, Ireland; IN2P3, France.

ZTF Lightcurve of BZQJ0253+0006